Complexes of tetracyclines and derivatives thereof



United States Patent ABSTRACT OF THE DISCLOSURE This invention relates to complexes of the general formula CH3 X wherein R is hydrogen or halo, R is hydrogen or lower alkyl, R is hydrogen or hydroxy and together R and R is lower alkylene, R is hydrogen or hydroxy, R is hydrogen ofpyrrolidinomethyl; and each X is. lower alkyl,

3,360,560 Patented Dec. 26, 1967 I The novel complexes of this invention may be prepared in accordance with the process of this invention beginning with starting material of the formula wherein R, R R R and R are as hereinbefore defined.

phenyl or trihalomethyl provided that at least one X is trihalomethyl. These complexes possess antibiotic activity and are effective for such purposes against such microorganisms as Staphylococcus aureus 209 P, Escherichia coii and Mycobactcrium tuberculosis.

This invention relates to new and useful complexes. More particularly, this invention relates to complexes of the general formula 1 wherein R may be hydrogen or halo (e.g., chloro); R may be hydrogen or lower alkyl (e.g., methyl); R may be hydrogen or hydroxy; and together R and R is lower alkylene (e.g., methylene); R may be hydrogen or hydroxy; R may be hydrogen or pyrrolidinomethyl; and each X may be alkyl, aryl or perhaloalkyl; provided that at least one X is perhaloalkyl and preferably perfluoroalkyl.

The novel complexes of this invention possess antibiotic activity and are eflective for such purposes against such microorganisms as Staphylococcus aureus 209P, Escherichia coli and Mycobacterium tuberculosis; the dosage and/or concentration determined by the particular complex employed and the requirements of the patient.

Among the starting materials which may be employed in the practice of this invention may be included, inter alia, tetracycline; chlortetracycline; 6 demethylchlortetracycline; oxytetracycline; 6 deoxy 6 demethyltetracycline; 6 demethyltetracycline; 6 methylenetetracycline; pyrrolidinomethyltetracycline; and other like compounds.

The starting material of the instant invention are first dissolved or suspended in an inert, anhydrous solvent, such as 1,2 dimethoxyethane, tetrahydrofurane, dioxane, ethyl acetate, chloroform and the like and are then treated with a polyhalogenated oxygen-containing hydrocarbon such as polyhalogenated ketone, such as a polyfluorinated ketone, for example, hexafluoroacetone, dichlorotetrafiuoroacetone, trifluoromethylphenyl ketone, trifluoroacetone and other like ketones to yield the novel complexes of the instant invention.

Example 1 Anhydrous tetracycline (4.94 g.) is dissolved in 15 ml. of 1,2 dimethoxyethane in a 250 ml. flask. Hexafluoroacetone is bubbled through this solution until the vapors fill the flask. The flask is stoppered and the contents are stirred magnetically. After one hour the product crystallizes, forming a thick yellow mass.

The crystals are collected on a filter and washed sparingly with additional cold 1,2 dimethoxyethane. The yield is 6.64 g. (97.2%), [a] 187.5 (MeOH). Further purification can be achieved by recrystallization from chloroform or methanol-chloroform. The analytical sample has the following properties:

Melting point: decomposes above 190 in an evacuated capillary.

U.V.: EtOH) 269 m (5: 19,000), 362 m a: 16,500).

[a] (-)l08i0.5 (c. 1.6, dimethoxyethane).

[a] ()189i0.5 (c. 1.3 methanol).

Microanalysis: Calcd for C H O N F F, 18.67; N, 4.59; M.W. 610. Found: F, 18.08; N, 4.38; N.E. (HCIO 597.

NMR (pyridine) C-6 methyl 8.281- singlet, C-4 hydrogen 5.627 broad singlet, C-4 dimethylamino 6.821 singlet.

Example 2 Tetracycline (444 mg., 1.00 mmoles) is dissolved in two milliliters of tetrahydrofuran and treated with symdichlorotetrafluoroacetone (199 mg., 1.00 mmoles). The solvent is removed under vacuum and the oily residue is triturated with hexane to convert the complex into a filterable, powdery form. The product is collected on a filter and dried under vacuum at room temperature.

Example 3 Anhydrous 6 demethylchlortetracycline (0.498 g.) is suspended in 15 ml. of chloroform in a 50 ml. flask. The liquid and void space contained in the flask is satu- Example 2 is followed but equivalent amounts of oxytetracycline, 6 demethyltetracycline, pyrrolidinomethyltetracycline or chlortetracycline are substituted for the 6 demethylchlortetracycline.

Similarly, like results are obtained when equivalent amounts of dichlortetrafiuoroacetone or trifiuoroacetone or trifluoromethylphenyl ketone are substituted for hexafluoroacetone.

These complexes are more soluble in organic solvents such as chloroform or ethyl acetate than the starting tetracycline derivative and are detectable as U.V.-absorbing, bioactive spots after paper chromatography using McIlvaines pH 4.5 buffer as stationary phase and ethyl acetate as moving phase.

Example 4 The in vitro antibiotic activity of the novel tetracyclinehexafluoroacetone complex (THFC) of the invention as compared to that of the hydrochloride salt of tetracycline can be seen from the following table:

TABLE 1.IN VITRO COMPARISON OF ACTIVITY OF TETRACYCLINE HEXAFLUOROACETONE COMPLEX (THE) A ND TETRACYCLINE HCl Inoeulum THFC 2 Tetra- Organism Size, cycline cells/ml. H01 2 Staphylococcus aureus 209P 10 0. 22 0.23 Staphylococcus aureus 2091i... 10 0.05 0. 04 Staphylococcus aureus 2406 10 50. 50. 0 Staphylococcus aureus 3188 3 10 50. 0 50. 0 Escherichia coli 3552 3 50. 0 50. 0 Escherichia call 2975 3 10 1. 1 1. 3 Salmonella schott'muelleri 3850 10 0.3 0.2 Mycobactcrium tuberculosis var B C G 10 1. 4 1. 4 Candida albicans 1539 10 50. 0 50. 0 Trichophyton rncntagrophytes 10 50. 0 50. 0

1 Twoiold tube dilution assay. 2 Minimum Inhibitory Concentration, meg/ml. B Tetracycline-resistant Strain.

The invention may be variously otherwise embodied within the scope of the appended claims.

What is claimed is:

1. A complex of the formula wherein R is selected from the group consisting of hydrogen and pyrrolidinomethyl; R is selected from the group consisting of hydrogen and halo; R is selected from the group consisting of hydrogen and lower alkyl; R is selected from the group consisting of hydrogen and hydroxy; and together R and R is lower alkylene; R is selected from the group consisting of hydrogen and hydroxy; and each X is selected from the group consisting of trihalomethyl, lower alkyl and phenyl, provided that at least one X is trihalomethyl.

2. Tetracycline hexafluoroacetone complex. complex.

3. 6 demethylchlortetracycline hexafluoroacetone.

4. The process of preparing the complexes of claim 1 which comprises reacting a compound of the formula R2 R3 CH fluoroacetone, dichlorotetrafluoroacetone, and trifluoromethylphenyl ketone.

7 References Cited UNITED STATES PATENTS 2/1966 Martell 260559 NICLTOLAS S. RIZZO, Primary Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,360,560 December 26, 1967 Frank L. Weisenborn et ale It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 31, after "invention." insert The invention may be illustrated by the following examples column 4, line 25, strike out "comp1ex."; line 26, after "hexafluoroacetone" insert complex Signed and sealed this 21st day of January 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Altosting Officer Commissioner of Patents 

1. A COMPLEX OF THE FORMULA 